Field of the Invention
The present invention relates to transporting large towers by railroad. More specifically, the present invention relates to a system and method for transporting large towers and tower sections, such as towers used to support commercial wind turbines, using adjustable position fixtures to accommodate tower sections of various lengths and weight profiles.
Description of the Related Art
Large-scale wind turbines are used to generate electrical power. Such wind turbines consist of a tall tower with a generator nacelle rotatably coupled about the top of tower's vertical axis. A rotor hub extends out a horizontal axis of the nacelle. Two or more turbine blades are connected to the rotor hub at right angles to the horizontal axis. During operation, prevailing winds cause the turbine blades to rotate about the rotor hub's horizontal axis. The rotational forces are coupled to a generator within the nacelle, which produces electricity. The nacelle rotates about the vertical axis of the tower to maintain the wind turbine blades in proper orientation to the direction of the prevailing winds.
The various components of a large-scale wind turbine may be manufactured at different geographic locations, which may be anywhere in the world. These components must then be transported to the ultimate power generation site, assembled, erected, and placed into operation. Since the manufacturing operations may be spread across the world, transportation of the components to the generation site may utilize all modes of transportation, including ships, barges, trains and trucks. The various components are expensive to manufacture, and include delicate components that must be protected and handled properly during transportation. The transportation issues are exacerbated in that the components may be transported using plural modes during their journey. For example, a wind turbine tower manufactured in Denmark may travel by ship across the ocean, then via railroad to a location in the geographic area of the generation site, and then finally by truck to the ultimate destination. Mounting fixtures are needed to adapt the particular component being transported to each mode of transportation.
Generally, longer rail flatcars are preferred for transpiration of towers and tower sections. Presently, the inventory of 89-foot long flatcars in the railroad industry is declining, while the usage demand for these cars is increasing, particularly with regards to the transport of wind turbine tower sections. Given this constraint, users are demanding systems that allow for the quick reconfiguration of the available flatcars, as needed to transport wind turbine tower sections of varying length. Reconfiguration is desirable because this limited fleet of rail assets must be used for a variety of towers and tower sections that may have various lengths and weight distribution profiles, and which must be loaded onto the railcars in a manner that satisfies the design criteria of the railcars. Fixed saddle systems for the railcar transport of wind turbine tower sections are shown in co-assigned U.S. Pat. No. 8,529,174, which is incorporated herein by reference for all purposes. Thus it can be appreciated that there is a need in the art for a system and method addressing the problems related to transportation of long and heavy towers and tower sections via rail.